This study is designed to determine if (1) the 5-hydroxytryptophan induced increase in serum ACTH, cortisol and B-endorphin is significantly greater in unmedicated, manic and depressed patients than in non-psychiatric controls; (2) the treatment with tricyclic antidepressants decreases the 5-HTP-induced increased cortisol response and treatment with lithium will increase the response; (3) the cortisol response to 5-HTP will correlate with duration of illness and ratings of psychopathology/depression.